Evaluating Enzymes That Generate Genotoxic Benzo[a]pyrene Metabolites Using Sensor Arrays

Abstract

Arrays with individually addressable, demountable electrodes coated with ultrathin DNA/enzyme films were evaluated to estimate relative rates of genotoxic bioactivation of benzo[a]pyrene (BP) for several different enzymes simultaneously. Specifically, cytochrome (cyt) P450cam, cyt P40 1A2, and myoglobin in the array were activated with H₂O₂ to metabolize BP to genotoxic metabolites. DNA damage by the metabolites was detected by increases in square wave voltammetric oxidation peaks using Ru(bpy)₃²⁺ as catalyst. Cyt P450cam and cyt P450 1A2 showed 3-fold higher activity for genotoxic bioactivation of BP than myoglobin. The ability of the arrays to generate and detect metabolite-based DNA damage simultaneously for several enzymes is a rapid and promising approach to identify and characterize enzymes involved in genotoxicity of drugs and pollutants.